Possible debris sightings by Chinese, Australian and New Zealand military planes did not yield any solid clues in one the most baffling mysteries, compounding the frustration of families who have been waiting more than three weeks to get detailed and confirmed information on the 239 missing passengers on board Flight MH370.
The search for the Malaysia Airlines jet entered the 22nd day today with 10 aircraft and eight ships tasked to scour the Indian Ocean, after early sightings in the new search zone drew a blank.
Some 29 family members from China arrived in Kuala Lumpur and held a news conference at their hotel, imploring officials to be more transparent.
"We want evidence, we want truth and we want our family," said Jiang Hui, the families' designated representative. The crowd chanted the same words.
He also asked Malaysia to apologise for releasing confusing information and for announcing on March 24 that the plane had crashed without "direct evidence".
Meanwhile, eight planes and a number of ships scoured some 252,000 square kilometres of water yesterday for signs of the plane, with aircraft reporting sightings of objects similar to those reported on Friday, the Australian Maritime Safety Authority (AMSA) said.
Australian Prime Minister Tony Abbott described the "intensifying search effort" as positive because objects "have been recovered from the ocean".
A Chinese and an Australian ship failed to identify debris from the missing plane after their first day in the new search area about 1,850 km west of Perth.
Chinese patrol ship Haixun 01 and Australia's HMAS Success both retrieved objects but none was confirmed to be from flight MH370 that went missing over three weeks ago, AMSA said.
The Australian navy ship given the job of finding the black box recorder of flight MH370 is preparing to leave Perth to join search operations.
The towed pinger locater on the Ocean Shield has a range of 1.6km and depth capability up to 6,000m.
An unmanned US underwater drone will also be on board, ready to dive once the pinger locater has found a signal to map the sea floor and photograph potential debris there.
"Finding the black box flight recorder of the missing Malaysia Airlines passenger jet is simply untenable as things stand at the moment," Captain Mark Matthews, the US Navy officer who will lead the search has conceded.
"It all depends on how effective we are at reducing the search area," said Matthews, a search-and-recovery expert who was involved in the two-year search to find the black box of Air France flight 447, which crashed in the Atlantic Ocean in 2009.
Former Australian defence force chief Angus Houston would head a new unit to help in the search involving the militaries of seven nations -- Australia, China, Malaysia, Japan, New Zealand, South Korea and the US.
Houston would lead the new Joint Agency Coordination Centre (JACC) based in Perth, "to coordinate the Australian government's support for the search into MH370," Abbott said.
Ten planes will fly over 319,000 square kilometres, the AMSA said.
Weather in the search area is forecast to worsen with light showers and low clouds, though search operations are expected to continue, the authority said.
Eight ships will join the search by the end of the day. All ships will seek to locate and identify objects sighted by aircraft over the past two days.
Aircraft involved in the hunt for the plane have so far reported seeing a number of objects of various colours floating in the sea in the new area.
A Chinese aircraft yesterday spotted three unidentified floating objects coloured white, red and orange. White and red were among the colours on the outside of the missing plane.
Officials said the focus to the new area about 1,100 km northeast of the previous search zone changed after radar data showed the plane had been travelling faster that previously thought, thus burning more fuel.
The Beijing-bound jetliner - carrying 239 people, including five Indians, an Indo-Canadian and 154 Chinese nationals - had vanished after taking off from Kuala Lumpur and crashed in the remote southern Indian Ocean.